present invention relates to a pen cap for a writing instrument barrel and more particularly to a ventilated pen cap for a writing instrument barrel of the marking type.
Pen caps of various structures for writing instrument barrels are generally well known in the stationery art and, in fact, it more recently is known to provide a molded plastic pen cap for a writing instrument barrel of the marking type which includes an inner housing which defines a chamber open at one end for receiving the nib of a writing instrument barrel and a spaced flow-through open ended outer housing which receives the writing instrument barrel at the proximal end of the cap and defines a narrow passage with the inner housing at the distal end of the cap between the inner and outer housing with a thin spider with radially extending spaced spokes being provided adjacent the open, nib receiving end or proximal end of the inner housing. This known plastic cap further includes a sharp edged clip integral at the proximal end of the cap with an annular ring.
The present invention recognizes that even the more recent type of molded plastic type pen cap as above described has had its limitations in strength, durability, ventilation ability and protection of the marking nib to extend the shelf-life thereof. Recognizing the disadvantages of past pen caps including those of the more recent molded plastic ventilating type the present invention provides a molded plastic pen cap which provides ventilation when in both barrel assembled and disassembled relation, which provides increased cap body strength at the proximal end of the cap and which promotes enhanced ventilating air flow-through. Further, the present invention provides a cap structure which enhances nib assembly thereto and fluid medium shelf-life through narrowed, extending passages surrounding the nib protecting inner housing, the inner housing being located at the proximal end of the cap with the closing tapered end of the inner housing being located in a position comparatively removed from surrounding ambient conditions, at the same time, providing a venturi-like enhanced ventilating air flow along the narrow surrounding passages if needed. In addition, the unique and novel cap structure of the present invention not only provides a cap arrangement with increased proximal end strength, but also an arrangement which provides an extended clip integral therewith to satisfy the requirements of consumer small parts regulations. Moreover, the present invention provides a novel clip which is contoured to both avoid the undesirable sharp edges of past plastic clips and to avoid possible plastic defects which might otherwise occur during the molding process.
Various other features of the novel cap structure of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.